The behaviour of ionic conducting oxides was considered. It was shown that, if such an oxide was placed between short-circuited reversible electrodes that were exposed to different chemical potentials, the O ions moved essentially under the influence of a gradient of electrical potential.

Comment on Experimental Procedure for the Determination of Diffusion Coefficients in Ionic Compounds - Application to Yttrium-Doped Zirconia. M.Mokchah, E.Siebert, F.Millot, G.Boureau: Solid State Ionics, 1999, 126[3-4], 379-82